A Phase Readout Method for Wireless Passive Sensor Used in Pressure Measurement System

A phase difference detection method used for reading the resonant frequency through mutual coupling is designed to meet the pressure measurement in harsh environments, and a testing device of integrated modular by developing the hardware circuits is proposed. Description and discussion of the novel theoretical model in the phase readout system is presented, and a pressure test platform based on the phase difference detection is also established, which is to measure the frequency of a LC resonant sensor on the basis of 96% alumina ceramic substrate. The experimental results show that the proposed phase difference readout system presents sweep-frequency detection in the range of 1-100MHz bandwidth, and a high frequency resolution of 0.006MHz. Sensitivity of the sensor is approximately 0.225 MHz/bar from 1 bar to 2 bar. The accuracy and functionality of the phase readout system have emphasized a wider engineering application range, so that we can make it possible that the wireless passive LC resonant sensor revolves well in practical engineering occasions outside the laboratory environment.